Trypsin Digestion Pretreatment of Kelp Samples and the Iodine Speciation Analysis of Iodate, Iodide, MIT, and DIT by HPLC-ICP-MS

Table 1

Instrumental operating conditions.

Parameter	Operation setting
Experimental conditions for HPLC
Column	IonPac AS-14 anion-exchange column (4 mm × 250 mm, 10 μm)
Mobile phase	100 mmol·L^−1(NH4)2CO3, pH = 9
Elution mode	Multistep gradient: 0–1500 s: 0.8 mL·min^−1、
	1500–3300 s: 1.2 mL·min^−1
	1500 s–3300 s: 1.2 mL/min
Column temperature	28°C
Injection volume	20 μL
Experimental conditions for ICP-MS
Forward power	1550 W
Plasma gas flow	14.000 L·min^−1
Auxiliary gas flow	0.8000 L·min^−1
Nebulizer gas flow	1.0150 L·min^−1
Sampling depth	5.0 mm
Analytical model	KED (kinetic energy discrimination)
CCT flow	5.198 mL·min^−1
Dwell time	0.2 s